1. Field of the Invention
The present invention relates to a closure device for a drain pipeline and, more particularly, to a closure device suitable for mounting between a drain of a sink or washbasin and a drainpipe.
2. Description of the Related Art
The drain opening of a sink or washbasin is mostly installed with a drain to prevent sundries from flowing into a drainpipe of the sink or washbasin. However, the drain is not closed, and odor generated from dirt accumulated within the drainpipe will flow through the drain opening into an indoor space. In addition, pests such as cockroaches and mosquitoes might also climb into the indoor space through the drain, which might lead to the lowering of the environment hygiene quality of the indoor space.
The sink drain may be installed with a conventional closing device for blocking odor and pests. However, the sundries and residues in the discharged water are usually stopped by the closing device and get accumulated within the sink drain, leading to plugging of the pipeline. Further, cleaning of the sundries and residues in the closing device is always not easy. Furthermore, A U-shaped or S-shaped drain trap has been proposed for being mounted between the drain and the drainpipe of the sink or washbasin so that odor and pests can be prevented by the retained water in the U-shaped or S-shaped drain trap. However, if water is not discharged into the drain opening for a certain period of time, the water in the drain trap will get dried due to negative pressure in the drainpipe, and then the effect of blocking odor and pests will be lost. Further, it is troublesome to install the drain trap in existing drain pipelines.